CHAP. XX 



Heredity 333 



mitted ; peculiar soil conditions altered the root of the 

 carrot, and the result was transmitted. 



Semper gives a few cases such as Schmankewitsch's 

 transformation of one species of brine-shrimp {Ariemia) into 

 another, throughout a series of generations during which 

 the salinity of the water was slowly altered. 



Eimer has written a book of which even the title, " The 

 Origin of Species, according to the laws of organic growth, 

 through the inheritance of acquired characters," shows how 

 strongly he supports the afifirmative side of our question. 

 But much as I admire and agree with many parts of Eimer's 

 work, I do not think that all his examples of the inheritance 

 of acquired characters are cogent. One of the strongest 

 is that cereals from Scandinavian plains ti-ansplanted to 

 the mountains become gradually accustomed to develop 

 more rapidly and at a lower temperature, and that when 

 returned to the plains they retain this power of rapid 

 development. I am incHned to think that the strongest 

 part of Eimer's argument is that in which he maintains that 

 certain effects produced upon the nervous system by peculiar 

 habits are transmissible. 



(4) Another mode of argument may be considered. To 

 what conception of evolution are we impelled if we deny 

 the inheritance of acquired characters ? Weismann believes 

 that he has taken the ground from under the feet of 

 Lamarckians and BufFonians, who believe in the inheritance 

 of functional and environmental variations. The sole fount 

 of change is to be found in the mingling of the kernels of 

 two cells at the fertilisation of the ovum. On these varia- 

 tions natural selection works. 



But even if we do not believe in the inheritance of 

 acquired characters, it is open to us to maintain that by 

 cumulative constitutional variations in definite directions 

 species have grown out of one another in progressive evolu- 

 tion. Thus we are not forced to restrict our interpreta- 

 tions of the mai-vel and harmony of organic nature to the 

 theory of the action of natural selection on indefinite for- 

 tuitous variations. 



Prof. Ray Lankester's convictions on this subject are so 



